Wiring for light with a 2 gang switch with 3 core cable

[Marilo]

I hope someone can help.

When removing the switch plate to the hall light two wires were hanging loose so I was unable to identify where they should go on the replaced switch plate. This plate looks very complicated as it operates the downstairs and upstairs hall light. Also there is another switch (one gang) in the hall that operates the downstairs light in a different location and another one gang switch that operates the upstairs light, upstairs. (3 switches, 2 lights)

Behind the two gang switch there are 3 grey cables. Two have 3 core wire (green/yellow, red, blue and yellow) and the third grey wire has two core (earth and two red wires).

I have included a diagram. I hope it is clear. The two wires red and blue marked with a question mark are the wires that I can't identify a place for. I am not sure that the other wires are in the correct position either as I have always had a problem with this switch not working in conjunction with one of the one gang switches.

I hope someone has some ideas cos I've looked at the wiring diagrams for lighting circuits and can't see any relating to 3 core wire.

 

[Marilo]

//media.diynot.com/153000_152192_27785_56321406_thumb.jpg

 

[riveralt]

Have a look a Wiki - electricks uk under lighting

//www.diynot.com/wiki/electrics:lighting:two_way_lighting

 

[Marilo]

On the back of the switch there are 6 connectors would that mean that it is a 3 way 2 gang switch?

 

[riveralt]

If this switch is a three gang two way switch is will have a total of 9 terminals on the rear - three terminals per gang. Each one will have a C L1 and L2.

If it has six terminal to the rear then it is likely that you have a three gang one way switch - each gang will have a C and L1 only.

As well as describing how the wiring is connected by colour of cable you also need to show which cable colour goes into which terminal - which is why I have referred you to Wiki.

Failing that take photographs because your drawing is confusing.

 

[sparkwright]

I would put the red in the empty terminal
and
the blue in the terminal that is top centre on your diagram (it has a red already in it)

Without seeing inside your other switches, this is all I can go on. So impossible to give a definite answer.

Work safely. Isolate all circuits. Tighten all connections if loose.

 

[sparkwright]

The title suggests a 2 way 2 gang switch, which would normally have 6 terminals.

 

[Marilo]

Thanks everyone for your help. I will try your suggestion sparkwright and if it doesn't work I will post diagrams of the other two switches.

 

[Marilo]

Your suggestion of where to put the wires, sparkwright, has just fixed a light fitting that hasn't worked correctly for years. Thank you!